The present invention resides in a production system for garments or other products which are manufactured by mass production techniques. In particular, the present invention relates to apparatus and methods for controlling the work flow between multiple work stations where different work operations are performed to manufacture the product.
Mass production systems for products such as ladies dresses, men's shirts and suits and a wide variety of other products are well known in the art and have been used for several years to both control the flow of work between work stations in the manufacturing process and to keep track of completed work products, work in progress and labor and production costs. In the garment industry, the production systems generally include a plurality of work stations at which various types of equipment such as sewing machines, button holers and the like are operated by a skilled human operator, and a computer controlled conveyorized transport system for transporting garment parts or partially assembled garments from one station to another. Parts forming the garments are loaded the transport system, are moved from work station to work station where different work operations are carried out until a finished garment is produced, and then the garment is unloaded from the system for delivery to retail and other outlets for purchase by customers.
The series of work operations performed at the various work stations generally begins with the attachment of pre-cut garment parts or pieces to a carrier and the loading of the carrier and attached pieces onto the transport system that extends between the work stations. The transport system is controlled to deliver the carrier and garment pieces to a work station where the first in the series of work operations leading to complete manufacture of the garment takes place. The garment pieces and carrier are unloaded at the work station by a human operator who also performs the work operation on the garment pieces in conjunction with equipment at the work station. The first operation in a series may consist, for example, of sewing the first two garment pieces together on a sewing machine. The now-sewn pieces are then re-attached to the same or another carrier and are taken by the conveyor system to another work station where the next operation in the series is performed. The partially assembled garment is moved from station to station until the garment has been completely manufactured. The types of operations that are performed at each station for manufacturing a garment include sewing pieces together, hemming the work pieces, sewing linings into the work pieces, sewing cuffs to sleeves, sewing sleeves to the front and back panels, sewing pockets, installing buttons and button holes and numerous other operations in addition to inspections of the product at its various stages of manufacture.
The details of a conveyorized transport system of the type used in a garment manufacturing system is shown in U.S. Pat. No. 4,947,758 having the same Assignee as the present invention. The movement of garment pieces from station to station must be controlled, and an apparatus for tracking the movement of the garment pieces and partially assembled garments from station to station is disclosed in U.S. Pat. No. 4,700,633 also assigned to the Assignee of the present invention.
In any garment manufacturing facility, only one or a limited number of assembly areas or "sewing rooms" are available for manufacturing all types and styles of garments produced by the facility. Additionally, garments of different types and styles must be moved from station to station by the single transport conveyor system in accordance with the series of work operations that are peculiar to each of the garments. All garments do not go to all work stations in the progressive stages of assembly, and correspondingly, all work stations do not perform work operations on all of the garments processed through the production system. As a consequence, the production system in the sewing room must accommodate a wide variety of styles and sizes of garments at any given time.
Furthermore, the number of types and styles of garments that are in the system at any given time can readily exceed 20 or 30. Accordingly, the production systems of the prior art have employed computerized tracking systems not only for locating the garment parts and partially assembled garments at any point in time, but also for scheduling the movement of the partially assembled garments and parts from one work station to the next available work station having the capability of performing the next required work operation.
The trend in the garment industry has been to produce smaller quantities of garments of a given style and to offer a greater variety of styles to the customer. This trend is reflected in the increased number of styles or product that must be handled by the production system at any given time. As a consequence, a control system for handling a much higher quantity of data is needed. The higher quantity of data also introduces greater complexity in the programming of the control system to accommodate, for example, changes in the work assignments within the production system. For example, if a piece of equipment breaks down at a particular work station, the work operations normally scheduled for that work station must be shifted elsewhere. The burden of reprogramming the system to direct the goods to other stations suitable for each style of product increases in direct proportion to the number of styles involved.
It is, accordingly, a general object of the present invention to provide a production system which is designed to handle a large number of products of different types and styles and which is designed to more easily accommodate changes in the work station assignments in spite of the increased volume of data being handled.